The invention is directed to one-way anti-back flow valves, and more particularly to anti-backflow valves suited for use as passenger vehicle cabin exhaust valves.
One-way or anti-back flow valves are used in many different applications and have many different forms. One such application is as a valve for preventing the back flow of air, into passenger vehicle cabins. The valve both seals the cabin against the entry of poisonous fumes and the like, and vents the cabin to prevent or relieve an undesired increase of pressure therein. Such pressure increases can be caused by the operation of the heating, ventilating and air conditioning system, or by the slamming of a door of a vehicle when all of the windows are rolled up. Valves designed to serve as cabin air exhausters must both seal against back pressure, permitting very little air to leak into the cabin, and must open at very low cabin pressure to prevent or quickly reduce any significant increase in cabin pressure. Standards for acceptable flow rates are established by automotive companies.
Cabin air exhausters are typically spring or gravity operated flapper valves, with the flapper being formed of a relative soft rubber or rubber-like material. The flappers are hinged along a top edge in some manner, and hang vertically responsive to gravity. Back pressure tends to force the flappers against the supporting plate. Elevated cabin pressure pushes the flapper away from the plate, allowing cabin air to escape. One problem with such valves is that the desired level of sealing is difficult to consistently achieve. A limitation of valves relying exclusively on gravity to close is that gravity biased valves are sensitive to orientation. The valves must typically be oriented in an upright position on a vertical surface to operate. Another concern is that the flapper may flutter, creating undesired noise when open when air is passing through at a high rate of flow. If a spring is used to provide a more positive closing of the flapper than is possible with gravity, the cabin pressure needed to initiate exhausting will be undesirably increased.
It is desired to provide a one way valve which seals effectively against back flow from a first side while opening at relatively low positive pressures on the second side independent of orientation.
A one-way valve includes a plate and a flexible vane. The plate has a vent opening of a first size and shape. The plate has a first curvature. The flexible vane has a second curvature distinct from the first curvature. The vane is fixed to the plate in a manner facilitating the deflection of the vane between an open position and a closed position. The vane is in a bent condition in the closed position. The vane conforms to the first curvature of the plate over the vent opening, and covers the vent opening in the closed position. The vane is elastic throughout a range of deflection associated with the vane moving between the closed position and the open position.
A one-way valve includes a plate and a flexible vane. The plate has a vent opening of a first size and shape. The plate has a first curvature. The flexible vane has a second curvature distinct from the first curvature. The vane is fixed to the plate by a tab extending from a side of the vane. The vane is in a bent condition in a closed position. The vane covers the vent opening in the closed position. The vane conforms to the first curvature of the plate over the vent opening and covers the vent opening in the closed position. The vane is elastic throughout a range of deflection between the closed position and an open position. The tab is formed integral and unitary with the vane wherein the tab is a living hinge about which the vane pivots between the open position and the closed position.
A one-way valve includes a concave plate, a flexible vane, and a means for attaching. The concave plate has a vent opening of a first size and shape. The flexible vane has a substantially flat shape in a free state. The vane covers the opening. The vane is sufficiently flexible that it conforms to a curvature of the plate in a closed position. The vane is elastic throughout a range of deflection between the closed position and the open position. The vane is sufficiently stiff to develop a desired sealing load when forced to conform to the concave plate. The means for attaching is for attaching the flexible vane to the concave plate and enables the desired deflection of the vane between the open position and the closed position.
A one-way valve is provided which seals effectively against back flow from a first side while opening at relatively low positive pressures on the second side independent of orientation.